1. Field
An electrode composition for a capacitive deionization apparatus and an electrode for a capacitive deionization apparatus are disclosed.
2. Description of the Related Art
In some regions, domestic water may include large amounts of minerals. In Europe and other regions, limestone substances frequently flow in underground water, and thus tap water in these regions typically contains a large amount of minerals. High mineral content in water (i.e., hard water) may have the disadvantage of easy generation of lime scales in interior walls of pipes and a sharp decrease in energy efficiency when used for home installations, for example, in a heat exchanger or a boiler. In addition, hard water is typically inappropriate for washing clothes or dishes. Therefore, there has been a demand for technology for removing ions from hard water to generate soft water, in particular, in an environmentally-friendly manner. Further, demands for seawater desalination have increased as larger areas of the world are suffering from water shortages.
A capacitive deionization (CDI) apparatus is a device for applying a voltage to porous electrodes having nano-sized pores to generate a polarity, thereby adsorbing ionic materials from a medium such as hard water onto the surface of the electrodes and thus removing the same therefrom. In the CDI apparatus, when a medium containing dissolved ions flows between two electrodes of an anode and a cathode and DC power having a low potential difference is applied thereto, the anionic components and the cationic components among the dissolved ions are adsorbed and concentrated onto the cathode and the anode, respectively. When an electric current flows in a reverse direction between the two electrodes by, for example, short-circuiting the two electrodes, the concentrated ions are desorbed from the electrodes. Since the CDI apparatus does not require a high potential difference, its energy efficiency is high, harmful ions may be removed together with the hard components when the ions are adsorbed, and its recycling process does not need any chemicals.